Broken 4 pole 3s brushless motor

hello everyone, I have a new RC buggy that I have been running pretty heavy in dusty and dirty conditions. One day my motor stopped working. I took it apart and found tons of dirt so I cleaned it out. Once it was cleaned out I realized on the bottom my counterweights were missing. Now the magnet sticks to the sides. Does anyone know where to buy these counterweights and then how to put the shield back on.

I would replace the motor, also not a bad idea to remove the new motor and blow it out with some compressed air every time you do a rebuild which I would do every 20-25 battery packs to clean the bearings, replace fluids in shocks/diff and apply fresh grease on all the rubber seals